In LTE systems, downlink and uplink transmissions may be organized into two duplex modes: frequency division duplex (FDD) mode and time division duplex (TDD) mode. The FDD mode uses a paired spectrum where the frequency domain is used to separate the uplink (UL) and downlink (DL) transmission. FIG. 1A is a graphical illustration of an uplink and downlink subframe separated in the frequency domain for the FDD mode. In TDD systems, an unpaired spectrum may be used where both UL and DL are transmitted over the same carrier frequency. The UL and DL are separated in the time domain. FIG. 1B is a graphical illustration of an uplink and downlink subframe sharing a carrier frequency in the TDD mode.